Noemie Mayombo's late basket handed Belgium a 64-62 come-from-behind triumph over Serbia in Group E on Monday.
With the score at 62-62 with five seconds remaining, Mayombo's layup put Belgium in front.
Serbia had a chance to take the game to overtime but Jelena Prvulovic's desperate jumper was swatted by Anne-Sophie De Bondt as Serbia suffered their first defeat.
"We had a very difficult first round," said Belgium coach Arvid Diels. "We were in the group with Spain and Latvia.
"We had a close game against Latvia and we lost by three points.
"It's great for this group to win a close game like this one.
"Serbia is in the top three of this tournament and they are very good team."
Belgium trailed 47-35 midway through the third quarter but reeled off 16 of the next 18 points in the game to take a 51-49 lead with seconds to go in the frame.
Both teams traded leads in the final quarter but Belgium prevailed.
Jana Raman had a game-high 23 points and pulled down 10 rebounds for the victors while team heroine Mayombo finished with 20.
Belgium limited Serbia to 17 of 56 (30.3%) from inside the arc while they finished 19 of 39 (48.7%).
"Our tactics were not to allow Serbia to make inside shots because they had done that against Sweden and instead to force them to make outside shots," said Diels. "We did that and they didn't make their outside shots."
Serbia, who out-rebounded Belgium 50-40, were four of 13 (30.8%) from long-range.